Federally Protected Mussel Survey in Line Creek

Peachtree City’s Airport (Falcon Field) lies within the Line Creek water-shed. Two small, unnamed streams flow through the airport property and drain into Line Creek. Historically, Line Creek had an abundant and diverse mussel fauna, composed of approximately 25 species including three species designated as federally endangered: Shiny-rayed pocketbook (Lampsilis subangulata), Gulf moccasinshell (Medionidus penicillatus), and Oval pigtoe (Pleurobema pyriforme); and one species designated as federally threatened: Purple bankclimber (Elliptoideus sloatianus). The airport was considering expanding, and because of the potential presence of federally protected species in the direct and indirect impact zone of the expansion project, a survey for native mussels was conducted at the confluence of the two tributaries and Line Creek.

The mussel survey of Line Creek in the vicinity of the two unnamed tributaries was conducted using a timed search. Searchers began at the downstream end of the survey reach and slowly moved forward as they probed the substrate for live mussels and relic shells. Nearly all habitats were easily accessible because of the low water conditions during the survey period.

A total of 38 live mussels and three relic shells representing seven species were found in the three contiguous reaches of Line Creek adjacent to the two tributaries. Numerically, the dominant species was the Variable spike (Elliptio pullata). Oval pigtoes (Pleurobema pyriforme) were found in all three reaches. One Oval pigtoe was found between the mouths of the two tributaries, two were found upstream of the tributaries, and five were found downstream of the tributaries. Prior to the present survey in the vicinity of the two unnamed tributaries, the only known record of the Oval pigtoe in Line Creek was in 1992, when six individuals were found approximately 300 m downstream of the SR 54 bridge.